When plant deleterious Pseudomonas putida ATCC 39167 and Pseudomonas fluorescence A225 are grown in iron deficient culture medium, they produce and secrete two novel yellow-green fluorescent pseudobactims each; P39167-I, P39167-II, PA225-I and PA225-II. Pseudobactin P39167-I has a molecular formula of C46 H64 O23 N13 and molecular weight of 1166.4, whereas the molecular formula of P39167-II is C46 H63 O22 N13 with a molecular weight of 1149.4. Pseudobactin PA225-I has a molecular formula of C46 H64 O24 N13 and a molecular weight of 118, whereas Pseudobactim A225-II had the molecular formula of C46 H63 O23 N13 and a molecular weight of 1165 g/mole. All four of the pseudobactins contain a 1,2 dihydroxy quinoline based chromophore and an octapeptide. The exact molecular mass and amino acid sequence for these peptides are being investigated by MALDI/TOF and FAB/tandem MS.